As soon as the engine is warm, the engine looses power?

Here are some additional areas to consider:

Exhaust Gas Recirculation (EGR) System:

Air/Fuel Ratio:

Throttle Position Sensor (TPS):

Idle Air Control (IAC) Valve:

Perform a compression test. Each cylinder should around 150 PSI +/- 10-15 PSI, and max difference between high and low should be no more than 15 PSI.
Get the engine warm and check the fuel pressure at the fuel rail/pressure regulator.
Check the output of the coil when the engine is hot, it should be bright blue.
Run a bottle of fuel system cleaner through the tank.

That, too.

Compression test was good. all cylinders read 160 with no difference. Fuel pressure drops when engine is warm. This is why the pump, filter and ignition control module were changed. Coil changed with plugs and wires. If engine runs well for 20 minutes, could timing still be off?

Check if the injectors and fuel pressure regulator are leaking this will drop the fuel pressure.

Since it seems to be fuel related, fuel pressure regulator? Would it fail only at normal operating temperature

Injectors tested good.

Check the FPR and could also be the fuel pump check valve-

What is the fuel pressure when cold and hot? It sounds a bit like vapor lock.

Timing isn't adjustable. It is a function of the timing belt cover and making sure marks are in the right position. If it slipped one tooth would it run right at low engine temperatures and not when the engine is warm?

The valve timing is the relationship between the camshaft and crankshaft positioning make sure its not 180deg off-Verify it and then come back

Ignition timing is set by loosening and rotating the distributor. And yes, if the ignition timing is off, it can run fine when cold, since the computer is in cold start mode. And then once the engine warms up, if the timing is not correct, it can cause issues. Does it make any noises while accelerating when hot?

engine sounds great when it starts and runs for first 15 minutes. It makes no noises when accelerating when hot. I don't think a 4 cylinder would run well cold 180 degrees out. This car does not have a distributor.

You have not answered anything about fuel pressure -maybe the fuel pump behaves during the 15mins then goes haywire when it heats up-Check and monitor the fuel pressure and get back with the readings before we can continue.

BTW we both know it doesn't have a distributor

The 93 Escort LX had a distributor. So if this one doesn't, it's had an engine change. As far as I recall, DIS wasn't introduced for this model until 95 or 96.

No... this is the 3rd 93 escort I've had and none have had a distributor cap. All use an ignition coil. If there is a distributor cap, I've never seen one.

According to the mechanic, fuel pressure drops when engine gets warm but at this point I'm not sure if I believe him.

and there have been 3 fuel pumps installed. I did the first one. The garage has done 2 more, claiming the first one they installed went bad in 25 miles.

A DIS system don't have a dizzy cap its a direct ignition system

Hook-up a fuel pressure tester to the fuel test port and monitor the pressure to confirm that the FP is doing its job-An EFI system has to have the correct pressure to function accordingly

Yeah, I know. I just didn't think that Ford had DIS systems that early, especially in the Escort. My 98 Escort had a distributor, while my 99 didn't. My 95 Contour was DIS, while my 93, 94 and 89 Tauruses all had distributors.

According to the mechanic the fuel pressure dropped when the engine got warm, the pressure dropped (at least until they replaced the 2nd fuel pump). It's not clear that they have measured the fuel pressure. I think it is something in the fuel control system but not sure what or how to diagnose.

You can borrow a fuel pressure tester from a parts store like Autozone, Pep Boys or O'Reilly. Fuel pressure dropping when the engine gets warm means that part of the fuel is vaporizing in the lines. Vapors compress while liquids don't.
Also make sure the air gap for the crank position sensor is set properly and that it is securely attached.

i thought vapor lock was not a problem in fuel injected systems. Since the pump is in the fuel tank and the system is pressurized, it seems like it would be very hard to get vapor lock. With vapor lock, once the car starts running rough, it would be impossible to start. That is not the case. The car starts fine even when warm, it just lacks power.

But the fuel pressure drops once the engine reaches operating temperature, according to your description. Vapor lock isn't as much of an issue in injected vehicles, as long as fuel pressure is maintained. And since the fuel has farther to travel after being pressurized, it has more time to reach the temperature at which vaporization can begin. This is why most fuel pumps pressurize the system to much higher than what injectors can handle, then the pressure regulator releases excess pressure before the fuel reaches the fuel rail and injectors.

The mechanic gave up and sent it to Ford. I've read several sites that said it could be the timing belt slipping a notch. The codes came back intermittent low voltage camshaft position sensor and intermittent low voltage crankshaft position sensor. The thing these two things have in common is timing. The timing belt had slipped one notch due to a failed harmonic stabilizer.

If you followed my 1st suggestion -the timing belt would have been fingered if the valve timing was checked-